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Dozens of celebrities may be running afoul of the law as they unite under the banner of one group that is seeking to prevent a method of gas drilling in New York state.

Artists Against Fracking opposes hydraulic fracturing, or fracking, and boasts members including Yoko Ono and actors Mark Ruffalo and Susan Sarandon.

The group says forcing water and chemicals deep into shale deposits to extract gas threatens drinking water and the environment. The group's website implores, "Tell Governor Cuomo: Don't Frack New York."

But the group and nearly 200 entertainers who are gaining attention and support in the dispute, which is splitting New Yorkers, aren't registered lobbyists, according to a search by The Associated Press of the database of the state Joint Commission on Public Ethics. State law is designed to disclose who is trying to influence government action, how much money they are spending and where the money's going.

"You spend money lobbying, you have to register," said David Grandeau, former executive director of the state lobbying commission and now an attorney representing lobbyists and clients.

There's no public record of how much money Artists Against Fracking has spent, but its website contains links for visitors to make donations, which are directed to the Sustainable Markets Foundation. Although the foundation is an established charitable organization and its donations are recorded publicly, it isn't registered with New York as a lobbying client, either.

Under New York law, however, it appears Artists Against Fracking is required to be a registered lobbyist because the law hinges on spending over $5,000. The group hasn't filed lobbying reports, so the amount it has spent and what it was spent on isn't known publicly. Experts in Albany say the website and public events appear to have cost well over $5,000.

The group hasn't responded to requests for comment in the past two weeks. The group's account executive at its public relations firm, Fenton of New York City, didn't respond to a request for comment.

The group includes Ono and Sean Lennon, the widow and son of musician John Lennon. They recently attended an anti-fracking event in Albany with Ruffalo, actors Zooey Deschanel, Alec Baldwin and Hugh Jackman, and singer Lady Gaga, along with other longtime activists such as David Crosby and Paul McCartney. None of them are registered to lobby in New York.

A week ago, Artists Against Fracking widely released a music video done through Skype from various locations featuring dozens of entertainers singing a Sean Lennon song, "Don't Frack My Mother." In it, Ono sings part of the chorus, "Don't frack me!"

Failing to register as a lobbyist is not a criminal offense. Commonly, when a person new to lobbying is believed to have failed to lobby as required by law to track the influence of money on public policy, that person is given a chance to submit a lobbing form and pay a $200 fee.

One of the main players supporting fracking, the Independent Oil & Gas Association of New York, is registered.

Lobbying is big business in New York. The New York Public Interest Research Group reported that more than $220 million was spent lobbying in 2011 — and that was before the fracking debate really heated up.

The biggest penalty for failure to follow the lobbying law resulted in a $250,000 fine against Donald Trump and others over casinos in 2000, and the Philip Morris tobacco company was hit with a $75,000 fine in 1999.

Over the years, several celebrities or their groups have been required to register as lobbyists. But whether celebrities must register hinges on its specific circumstances. The line between lobbying and free speech isn't bright or clear, and the Joint Commission on Public Ethics wouldn't comment; it referred the AP to the law for clarification.

Under state law, a lobbyist is defined as any person or organization "employed, retained" in "any attempt to influence the passage or defeat of any legislation ... or approval or disapproval of any legislation by the governor." That can include nonprofit groups and their unpaid advocates.

In the fracking case, the Assembly and the Senate Independent Democratic Conference have introduced laws that would delay a pending decision on drilling by Cuomo.

Grandeau was in charge when, in 2005, the lobbying commission accepted a $5,000 payment to settle a case against a coalition that included hip-hop mogul Russell Simmons, former NAACP head Benjamin Chavis and the former federal housing secretary — Andrew Cuomo.

The commission had insisted The Coalition for Fairness, which aimed at relaxing long sentences for drug offenses, was lobbying, while the coalition said it was exercising its right to free speech.

Earlier in 2005, an appellate court ruled Simmons and Chavis had failed to disclose how much they spent on a 2003 rally against the drug laws.

The ethics commission "does not comment on or confirm matters that may or may not be before it," said spokesman John Milgrim. "But laws requiring lobbyists and their clients to publicly disclose their lobbying are well known and the commission expects compliance."